Ireland coach Joe Schmidt would not be drawn on referee Glen Jackson's performance in Saturday's series decider against South Africa after the New Zealander chose to issue Springboks full-back Willie le Roux with only a yellow card for a dangerous collision with Tiernan O'Halloran.

Ireland coach Joe Schmidt would not be drawn on referee Glen Jackson's performance in Saturday's series decider against South Africa after the New Zealander chose to issue Springboks full-back Willie le Roux with only a yellow card for a dangerous collision with Tiernan O'Halloran.

Two weeks after CJ Stander was shown a red card for a high challenge on Pat Lambie in Ireland's win in Cape Town and was subsequently banned for the second Test defeat, the officials opted for leniency after O'Halloran was upended in the air and landed awkwardly.

The Connacht star needed a head injury assessment and although he passed and returned to the field, he was replaced at half-time as a result of a rib injury he picked up in the incident.

Ireland ultimately lost 19-13 to the hosts, who claimed a 2-1 series win on the back of a huge defensive effort.

Despite the apparent inconsistency in the officiating across the series, Schmidt kept his counsel on the call.

"I don't really make comments on those incidents, other people deal with them and I probably would still say we were disappointed with CJ's red card in the first game but I haven't got any comment to offer really on the incident this evening," he said.

"Look, we spent six hours going back through the game to deliver our referee report.

"We send that back and we get a bit of feedback from referees.

"We use the official channels to comment, we don't comment publicly about referee performance because they are an incredibly important part of the game, they have an incredibly difficult job to do and I think they go out to do it as best they can.

"We could probably point the finger at a few errors that we made today. We might have done enough to get over the line otherwise so referees are very human as well."

That was a theme for Schmidt who lamented his side's lack of a clinical edge in the Port Elizabeth defeat.

The tourists dominated possession and territory but could not take the chances they created, with Luke Marshall guilty of a poor pass to Keith Earls before half-time and Paddy Jackson left ruing a Faf de Klerk intercept as he attempted to put Andrew Trimble away.

"We showed a bit of inexperience to be honest, a few times," Schmidt said.

"What could have happened, what might have happened is something that those players will have learned.

"There's a 14-point swing just before half-time when we make a great break up the pitch, we're one pass away from putting Keith Earls away and the pass isn't efficiently delivered and we miss the opportunity with the forward pass.

"Faf de Klerk leaping to get that ball, there's not too many people around him and with a little bit of patience we could have made the most of that opportunity.

"The maul at that time was still upright and potentially could have kept going, I thought it was a great option to swing back and attack that short side with good numbers but you've got to be clinical, you've got to be efficient in your execution, because in a Test match you don't get too many invitations.

"We got a couple of nice invites tonight that we didn't turn up for."

At the end of a 17-Test, 52-week season, Schmidt's overriding emotion was one of disappointment that his team could not get the job done.

"I'm massively disappointed," he said.

"It's 12 years since we've been in this country. To grab the opportunity last week, to have it in our hand and to be pick-pocketed the way we were with a superb South African comeback and then today to have so much energy into a game after a 52-week season is testament to the fortitude of the players.

"But when you don't get what you're looking for, you're always going to be disappointed particularly when it was such a fine margin at the end of it.

"When your coaching, you want perfection but you've always to take a bit of pride in the work ethic that's delivered by you players."